this is pretty terrible, but keep in mind to get the badge of the day you just need to play- not play well. just go right to the end tab and give them a carrot or celery or whatever.
to actually answer people's concerns- Badge Of The Day seems to be working fine to me. Keep in mind the "buildings" its talking about isnt your attack units, but buildings you can place after you beat a level. So your going to have to beat 2 levels and then build on those spots.
I love the tools who always bump down "badge isnt working" posts and bump up the same stupid "dis game is good" posts. heaven forbid people see that somethings not working so they can fix it.
you only need 10 coins to buy 10 pellets, to get the achievement. so if the idea of a tricky platformer with lag and achievement windows popping up to hide the platforms doesnt appeal to you, know its a quick one ^_^